there's always always the scare mongers trawling the posts. In a perfect world then ok, everything should be by the book but the world isn't perfect .. thankyou for posting your experience.
For the amount of money involved and overstay day/s it's not a big deal with the proveable reason you have. Reschedule, within reason/ stay / chill/second chance to further enjoy the facilities..
I'm aware thanks however the requirement of onward travel is an official requirement for Thailand as it is for Vietnam..people should be aware prior to taking their first flight regardless of Tdac.